The present invention relates to a controllable distributing conveying system which is used for transporting people and goods of any kind inside and outside buildings. The controllable distributing conveying system according to the invention is of the kind comprising a rail network made up of continuous horizontal and vertical guide rails along which self-propelled conveying units travel. On these conveying units or conveying tractors are transported containers which are used to hold people or goods, the containers being loaded on and off-loaded automatically at stations by the conveying unit with no manual intervention and the stations being connected to the rail network and thus necessarily to one another. For this purpose branch lines may be needed, which may be referred to as passive elements and by which the conveying units are caused to change their direction of travel, a central control unit giving active orders to the conveying units for the purposes of switching-in and -out, stopping and starting and coupling and uncoupling containers, and receiving in return passive reports. Also, the location and status of conveying units and station requests for containers to be collected in the system may be reported and these converted in turn into orders and at the same time an inspection may be made of a stand-by point for conveying units into which all conveying units which have not been instructed to perform any conveying job are conducted and from which they can be called up. The control unit may also exert control over one or more container depots from which empty or waiting containers can be called up when stations require them and issue an order, or in which they can be collected.
It is known that distributing conveying systems are for example used to transport documents, mail, and materials in both a solid and liquid state inside and outside buildings and between them. Such conveying systems may also be used to transport people (using so called cabtrack personal rapid transit for example), luggage at airports, and the like. It is also possible for such systems to be designed for and installed retrospectively in existing buildings. With systems of this type a distinction must be made between continuous conveyor systems and individual conveyors, that is say electrified rail systems. Each operating position is connected to the system and it consists of a receiving and despatching point which are connected together to form a station.
Since there is a certain rate of operation at each operating position, the individual receiving points have an irregular supply, and the rates of arrival and despatch differ from station to station. In the case of both systems, conveyor compartments or containers are used to hold the goods being conveyed and these have manually moveable destination-indicating devices or pre-imprinted perforated or magnetic cards. After the destination indicator has been set at the station the containers of the continuous conveyor are inserted into the transport conveyor slot. The transporting movement is imparted by a continuously running belt or chain. In contrast to electrified rail systems, the transporting capability of continuous conveyors must be designed as to allow their belts or chains to withstand a sudden maximum load, namely the load generated by transporting all the containers, each carrying a maximum load, if they are fed into the system, which means making the motors driving the belts or chains excessively powerful. In addition, the belts have to be tensioned to different degrees to suit the load and climatic conditions. Because the belts and chains run continuously, there is greater wear on the deflector bearing rollers and belts, which thus require continual maintenance and may also produce additional noise.
In electrified rail systems, the containers have an additional aid in the form of an electric motor and drive units permanently connected to them. In newer designs, these drive units can be coupled and uncoupled manually as desired (e.g. the same drive can be used with containers of different sizes). The direct coupling of the transporting container to its undercarriage has the disadvantage that a supply of transporting units has to be held at the stations. This results in conveying units accumulating at various stations while other stations are short of conveying units. Procuring the conveying units which are lacking means an unnecessary load on the system as a result of units travelling empty, e.g. a current overload in certain sections of the track (a load beyond the capacity of the power supplies for those sections). The conveying unit is only used for actual transporting tasks for about 60 percent of the time and thus calls for a higher percentage of maintenance before giving an output equivalent to 100 percent employment on transporting tasks. The fetching of a conveying unit means an unnecessary wait for the operating personel, who cannot load the goods to be conveyed until the empty conveying unit has arrived, and who have to set the station indicator by hand.
The amount of space taken up by a station track is dependent on its capacity for conveying units. If the station track is short, all the incoming conveying units must immediately be sent out again, since otherwise the station will report that it is "occupied". A conveying unit intended for this station may not and cannot be switched out and therefore cruises round the system until the station spur has been cleared. The conveying units may have their power sources (batteries) or the drive units may be fed via current-carrying rails, as desired. These current-carrying rails are then part of the conveyor rails. In both cases, whether the trolleys have internal or external current sources, power supplies are needed. In the case of a current-carrying track where the supply source is not carried on board, a power supply feeds a stretch of track of given length. This length is dependent on the maximum output capacity of the individual power supply and on the number of consumers (conveying units) which may be travelling on this length of track. In the case of conveying units having on-board power sources, the units must be charged up again at specified points. Since the lengths of the sections of current carrying track are dependent on the maximum possible consumption by conveying units situated in them (which is particularly critical in ascending stretches), a large number of individual power supplies are required. When a maximum number of conveying units accumulate in a section, the power supply concerned is subject to a maximum load while other supplies are free of load to some extent. This means that the optimum use is not made of the overall capacity of all the supplies in the system. Since the current-carrying rails are very small in size, no assistance can be gained by having a single power supply to meet the total consumption of all the conveying units.
In the case of both continuous conveyors and rails conveyors, active switching points are needed for switching out purposes and these include moving parts and are given regular maintenance or if repairs are necessary have to be repaired on the spot, the locations concerned often being difficult of access since to save space the systems installed, as far far as possible, in suspended ceilings or shafts. Repairs means that one stretch or the whole of the system has to be shut down.
It is an object of the invention to provide a distributing conveying system which performs all conveying tasks in the optimum fashion, which reduces waiting time for the operating personel to a minimum, and which has few mechanical parts which require intensive maintenance and involve complicated processes of manufacture. The intention is also to avoid blockages in certain sections of track and to make it possible for assembly to take place quickly and without difficulty without special tools or drilling operations being necessary.